SPARC expression in CML is associated to imatinib treatment and to inhibition of leukemia cell proliferation. BMC Cancer. 2013;13:60. [PMID: 23383963 DOI: 10.1186/1471-2407-13-60]

Dynamic changes in the levels of sCD62L and SPARC in chronic myeloid leukaemia patients during imatinib treatment

WHAT IS KNOWN AND OBJECTIVE

Chronic myeloid leukaemia (CML) microenvironment is responsible for resistance of leukaemic cells to tyrosine kinase inhibitor, altered adhesion, increased proliferation and leukaemic cells growth and survival through the secretion of many soluble molecules. We aimed at monitoring soluble L-selectin (sCD62L) and secreted protein acidic and rich in cysteine (SPARC) levels in chronic phase chronic myeloid leukaemia (CP-CML) patients and assessing the impact of imatinib on these parameters.

METHODS

This prospective controlled clinical trial enrolled 35 subjects classified into two groups: control group included 10 healthy volunteers and CP-CML patients group included 25 newly diagnosed CP-CML patients received imatinib 400 mg once daily. sCD62L plasma levels, SPARC serum levels, breakpoint cluster region-Abelson1 (BCR-ABL1) %, complete blood count with differential, liver and kidney functions parameters were assessed at baseline and after 3 and 6 months of treatment.

RESULTS AND DISCUSSION

At baseline, sCD62L and SPARC were significantly elevated in CP-CML patients (p < 0.05) compared to control group. After 3 months of treatment, sCD62L was non-significantly decreased (p > 0.05), while surprisingly SPARC was significantly increased (p < 0.05) compared to baseline. Moreover, after 6 months of treatment, sCD62L was significantly decreased (p < 0.05) and SPARC was non-significantly decreased (p > 0.05) compared to baseline. In addition, sCD62L was significantly correlated with WBCs and neutrophils counts, while SPARC was significantly correlated with lymphocytes count at baseline and after 3 and 6 months of imatinib treatment.

WHAT IS NEW AND CONCLUSION

The elevated levels of sCD62L and SPARC at diagnosis in CP-CML patients could reflect their roles in CML pathogenesis and the dynamic changes in their levels during imatinib therapy might suppose additional mechanisms of action of imatinib beside inhibition of BCR-ABL. Furthermore, imatinib showed a significant impact on sCD62L and SPARC levels during treatment period.

A Systematic Review of Candidate miRNAs, Its Targeted Genes and Pathways in Chronic Myeloid Leukemia-An Integrated Bioinformatical Analysis

Chronic myeloid leukaemia is blood cancer due to a reciprocal translocation, resulting in a BCR-ABL1 oncogene. Although tyrosine kinase inhibitors have been successfully used to treat CML, there are still cases of resistance. The resistance occurred mainly due to the mutation in the tyrosine kinase domain of the BCR-ABL1 gene. However, there are still many cases with unknown causes of resistance as the etiopathology of CML are not fully understood. Thus, it is crucial to figure out the complete pathogenesis of CML, and miRNA can be one of the essential pathogeneses. The objective of this study was to systematically review the literature on miRNAs that were differentially expressed in CML cases. Their target genes and downstream genes were also explored. An electronic search was performed via PubMed, Scopus, EBSCOhost MEDLINE, and Science Direct. The following MeSH (Medical Subject Heading) terms were used: chronic myeloid leukaemia, genes and microRNAs in the title or abstract. From 806 studies retrieved from the search, only clinical studies with in-vitro experimental evidence on the target genes of the studied miRNAs in CML cells were included. Two independent reviewers independently scrutinised the titles and abstracts before examining the eligibility of studies that met the inclusion criteria. Study design, sample size, sampling type, and the molecular method used were identified for each study. The pooled miRNAs were analysed using DIANA tools, and target genes were analysed with DAVID, STRING and Cytoscape MCODE. Fourteen original research articles on miRNAs in CML were included, 26 validated downstream genes and 187 predicted target genes were analysed and clustered into 7 clusters. Through GO analysis, miRNAs’ target genes were localised throughout the cells, including the extracellular region, cytosol, and nucleus. Those genes are involved in various pathways that regulate genomic instability, proliferation, apoptosis, cell cycle, differentiation, and migration of CML cells.

iTRAQ-based quantitative protein expression profiling of biomarkers in childhood B-cell and T-cell acute lymphoblastic leukemia

Purpose

This study screened serum proteins to identify potential biomarkers for childhood B-cell and T-cell acute lymphoblastic leukemia (ALL).

Patients and methods

Serum collected from 20 newly diagnosed B-cell ALL, 20 T-cell ALL and 20 healthy children. The peptides from these samples were subjected to iTRAQ. Differentially expressed proteins (DEPs) were further validated by ELISA in 24 B-ALL, 24 T-ALL, and 24 healthy children.

Results

Bioinformatics analysis revealed several pathways, including atherosclerosis signaling, interleukin signaling and production in macrophages and clathrin-mediated endocytosis signaling, that were closely related to childhood T-cell ALL. Furthermore, four selected proteins, namely LRG1, S100A8, SPARC and sL-selectin, were verified by ELISA. These results were consistent with the results of the proteomics analysis.

Conclusion

Serum S100A8 may serve as new diagnostic biomarkers in childhood B-cell ALL and T-cell ALL.

B-Myb Mediates Proliferation and Migration of Non-Small-Cell Lung Cancer via Suppressing IGFBP3

B-Myb has been shown to play an important oncogenic role in several types of human cancers, including non-small-cell lung cancer (NSCLC). We previously found that B-Myb is aberrantly upregulated in NSCLC, and overexpression of B-Myb can significantly promote NSCLC cell growth and motility. In the present study, we have further investigated the therapeutic potential of B-Myb in NSCLC. Kaplan–Meier and Cox proportional hazards analysis indicated that high expression of B-Myb is significantly associated with poor prognosis in NSCLC patients. A loss-of-function study demonstrated that depletion of B-Myb resulted in significant inhibition of cell growth and delayed cell cycle progression in NSCLC cells. Notably, B-Myb depletion also decreased NSCLC cell migration and invasion ability as well as colony-forming ability. Moreover, an in vivo study demonstrated that B-Myb depletion caused significant inhibition of tumor growth in a NSCLC xenograft nude mouse model. A molecular mechanistic study by RNA-seq analysis revealed that B-Myb depletion led to deregulation of various downstream genes, including insulin-like growth factor binding protein 3 (IGFBP3). Overexpression of IGFBP3 suppressed the B-Myb-induced proliferation and migration, whereas knockdown of IGFBP3 significantly rescued the inhibited cell proliferation and motility caused by B-Myb siRNA (small interfering RNA). Expression and luciferase reporter assays revealed that B-Myb could directly suppress the expression of IGFBP3. Taken together, our results suggest that B-Myb functions as a tumor-promoting gene via suppressing IGFBP3 and could serve as a novel therapeutic target in NSCLC.

SPARC expression in gastric cancer predicts poor prognosis: Results from a clinical cohort, pooled analysis and GSEA assay

Background

The prognostic role of Secreted Protein Acidic and Rich in Cysteine (SPARC) in gastric cancer (GC) remains controversial. We investigated the clinical significance, the survival relevance, and potential function of SPARC in GC with resected samples, online gene set GSE62254, and cell line SGC7901.

Results

High immunostaining of SPARC significantly correlated with tumor differentiation (P = 0.004), and independently predicted shorter overall survival (OS) (HR = 1.446, P = 0.022), based on the current IHC evaluation. The accuracy of the results was further validated with 1000 times bootstrapping and the time-dependent receiver-operating characteristics (ROC) curves. The meta-analysis (pooled HR = 1.60, 95% CI: 1.01−2.53) confirmed SPARC as the predictor for reduced OS in GC. Moreover, the association between enhanced SPARC expression and Adriamycin (Adr) sensitivity was revealed by GSEA, and then confirmed by comparative cellular experiments, such as the protein level analysis of SGC7901and SGC7901/Adr cell line.

Materials and Methods

Immunohistochemistry (IHC) method was used to detect SPARC expression in 137 GC cases. Meta-analysis was performed based on 5 studies published in English on PubMed up to March 2016. GSEA was performed using online data set GSE62254 and GC-related functional gene sets derived from molecular signatures database (MSigDB). Western Blot was carried out to compare protein-level differences between gastric carcinoma SGC7901 cell line and Adr resistant SGC7901/Adr cell line. MTT assay was done to confirm the induction of SPARC on Adr sensitivity

Conclusions

Increased SPARC expression in GC led to a worse clinical outcome of patients and might induce Adr sensitivity of GC cells.

Monocytic myeloid-derived suppressor cells as prognostic factor in chronic myeloid leukaemia patients treated with dasatinib

Myeloid suppressor cells are a heterogeneous group of myeloid cells that are increased in patients with chronic myeloid leukaemia (CML) inducing T cell tolerance. In this study, we found that therapy with tyrosine kinase inhibitors (TKI) decreased the percentage of granulocytic MDSC, but only patients treated with dasatinib showed a significant reduction in the monocytic subset (M‐MDSC). Moreover, a positive correlation was observed between number of persistent M‐MDSC and the value of major molecular response in dasatinib‐treated patients. Serum and exosomes from patients with CML induced conversion of monocytes from healthy volunteers into immunosuppressive M‐MDSC, suggesting a bidirectional crosstalk between CML cells and MDSC. Overall, we identified M‐MDSC as prognostic factors in patients treated with dasatinib. It might be of interest to understand whether MDSC may be a candidate predictive markers of relapse risk following TKI discontinuation, suggesting their potential significance as practice of precision medicine.

The Heme Oxygenase System in Hematological Malignancies

SIGNIFICANCE

Several lines of evidence suggest that hematological malignancies exhibit an altered redox balance homeostasis that can lead to the activation of various survival pathways that, in turn, lead to the progression of disease and chemoresistance. Among these pathways, the heme oxygenase-1 (HO-1) pathway is likely to play a major role. HO catalyzes the enzymatic degradation of heme with the simultaneous release of carbon monoxide (CO), ferrous iron (Fe²⁺), and biliverdin. This review focuses on the role of HO-1 in various hematological malignancies and the possibility of exploiting such targets to improve the outcome of well-established chemotherapeutic regimens. Recent Advances and Critical Issues: Interestingly, the inhibition of the expression of HO-1 (e.g., with siRNA) or HO activity (with competitive inhibitors) contributes to the increased efficacy of chemotherapy and improves the outcome in animal models. Furthermore, some hematological malignancies (e.g., chronic myeloid leukemia and multiple myeloma) have served to explore the non-canonical functions of HO-1, such as the association between nuclear compartmentalization and genetic instability and/or chemoresistance.

FUTURE DIRECTIONS

The HO system may serve as an important tool in the field of hematological malignancies because it can be exploited to counteract chemoresistance and to monitor the outcome of bone marrow transplants and may be an additional target for combined therapies. Antioxid. Redox Signal. 27, 363-377.

Common extracellular matrix regulation of myeloid cell activity in the bone marrow and tumor microenvironments

The complex interaction between cells undergoing transformation and the various stromal and immunological cell components of the tumor microenvironment (TME) crucially influences cancer progression and diversification, as well as endowing clinical and prognostic significance. The immunosuppression characterizing the TME depends on the recruitment and activation of different cell types including regulatory T cells, myeloid-derived suppressor cells, and tumor-associated macrophages. Less considered is the non-cellular component of the TME. Here, we focus on the extracellular matrix (ECM) regulatory activities that, within the TME, actively contribute to many aspects of tumor progression, acting on both tumor and immune cells. Particularly, ECM-mediated regulation of tumor-associated immunosuppression occurs through the modulation of myeloid cell expansion, localization, and functional activities. Such regulation is not limited to the TME but occurs also within the bone marrow, wherein matricellular proteins contribute to the maintenance of specialized hematopoietic stem cell niches thereby regulating their homeostasis as well as the generation and expansion of myeloid cells under both physiological and pathological conditions. Highlighting the commonalities among ECM-myeloid cell interactions in bone marrow and TME, in this review we present a picture in which myeloid cells might sense and respond to ECM modifications, providing different ECM-myeloid cell interfaces that may be useful to define prognostic groups and to tailor therapeutic interventions.

Mesenchymal Stem Cells (MSC) Regulate Activation of Granulocyte-Like Myeloid Derived Suppressor Cells (G-MDSC) in Chronic Myeloid Leukemia Patients

It is well known that mesenchymal stem cells (MSC) have a role in promotion of tumor growth, survival and drug-resistance in chronic myeloid leukemia (CML). Recent reports indicated that a subpopulation of myeloid cells, defined as granulocyte-like myeloid-derived suppressor cells (G-MDSC) is increased in these patients. So far, the role of MSC in MDSC expansion and activation into the BM microenvironment remains unexplored. To address this question, here we use a specific experimental model in vitro, co-culturing MSC with peripheral blood mononucleated cells (PBMC) from normal individuals, in order to generate MSC-educated G-MDSC. Although MSC of healthy donors (HD) and CML patients were able to generate the same amount of MDSC, only CML-MSC-educated G-MDSC exhibited suppressive ability on autologous T lymphocytes. In addition, compared with HD-MSC, CML-MSC over-expressed some immunomodulatory factors including TGFβ, IL6 and IL10, that could be involved in MDSC activation. CML-MSC-educated G-MDSC expressed higher levels of ARG1, TNFα, IL1β, COX2 and IL6 than G-MDSC isolated from co-culture with HD-MSC. Our data provide evidence that CML-MSC may play a critical role in tumor microenvironment by orchestrating G-MDSC activation and regulating T lymphocytes-mediated leukemia surveillance, thus contributing to CML immune escape.

SPARC ectopic overexpression inhibits growth and promotes programmed cell death in acute myeloid leukemia transformed from myelodysplastic syndrome cells, alone and in combination with Ara-C treatment

Secreted protein acidic and rich in cysteine (SPARC) has a complex and pleiotropic biological role in cell life during disease. The role of SPARC in myelodysplastic syndrome (MDS) is not yet fully understood. In the present study, we investigated the role of SPARC protein overproduction in the proliferation and apoptosis of SKM-1 cells, an acute myeloid leukemia cell line transformed from MDS. SKM-1 cells were infected with the pGC-GV-SPARC vector. The cells were then assessed for proliferation and cell death following treatment with low-dose cytosine arabinoside (Ara‑C). The microarray analysis results revealed that samples from SPARC‑overexpressed cells compared to SPARC protein, in SKM-1 cells led to proliferation inhibition and promoted programmed cell death and these effects were greater when treated with Ara-C. The mRNA and protein expression levels of SPARC were detected by SPARC overexpression in cells treated with Ara-C resulting in a significant upregulation of the mixed lineage kinase domain-like (MLKL) gene expression and five other genes. The results showed that the necrotic signaling pathway may play a role when the two conditions were combined via the upregulation of the MLKL protein. MLKL upregulation in SPARC overexpressed cells treated with Ara-C, indicates necrosis as a possible cell death process for the SKM-1 cells under these stringent conditions.

Significance of expression of RIN1 and SIAH2 proteins in gastric carcinoma

AIM: To examine the expression of Ras and Rab interactor 1 (RIN1) and seven in absentia homologue 2 (SIAH2) proteins in gastric carcinoma and to analyze their relationship with clinicopathological factors.

METHODS: The expression of RIN1 and SIAH2 was detected by immunohistochemistry in 80 gastric carcinoma and 40 normal gastric tissues.

RESULTS: The positive rates of RIN1 and SIAH2 protein expression were significantly higher in gastric carcinoma than in normal gastric tissues (61.2% vs 32.5%, 60.0% vs 27.5%, P < 0.05 for both). In gastric carcinoma, RIN1 expression was related to tumor size, clinical stage, histopathological grade, lymph node metastasis and depth of invasion (P < 0.05 for all), but not to patients' age or gender (P > 0.05 for both); SIAH2 expression was related to clinical stage, histopathological grade, lymph node metastasis and depth of invasion (P < 0.05 for all), but not to tumor size (P > 0.05). There was a positive correlation between the expression of RIN1 and SIAH2 in gastric carcinoma (r = 0.607, P < 0.01).

CONCLUSION: The overexpression of RIN1 and SIAH2 might play an important role in the progression, invasion and metastasis of gastric carcinoma, and they may be used as early diagnostic markers and therapeutic targets for gastric carcinoma.

Epigenetic therapy of acute myeloid leukemia using 5-aza-2'-deoxycytidine (decitabine) in combination with inhibitors of histone methylation and deacetylation

BACKGROUND

The silencing of tumor suppressor genes (TSGs) by aberrant DNA methylation occurs frequently in acute myeloid leukemia (AML). This epigenetic alteration can be reversed by 5-aza-2'-deoxcytidine (decitabine, 5-AZA-CdR). Although 5-AZA-CdR can induce complete remissions in patients with AML, most patients relapse. The effectiveness of this therapy may be limited by the inability of 5-AZA-CdR to reactivate all TSGs due to their silencing by other epigenetic mechanisms such as histone methylation or chromatin compaction. EZH2, a subunit of the polycomb repressive complex 2, catalyzes the methylation of histone H3 lysine 27 (H3K27) to H3K27me3. 3-Deazaneplanocin-A (DZNep), an inhibitor of methionine metabolism, can reactivate genes silenced by H3K27me3 by its inhibition of EZH2. In a previous report, we observed that 5-AZA-CdR, in combination with DZNep, shows synergistic antineoplastic action against AML cells. Gene silencing due to chromatin compaction is attributable to the action of histone deacetylases (HDAC). This mechanism of epigenetic gene silencing can be reversed by HDAC inhibitors such as trichostatin-A (TSA). Silent TSGs that cannot be reactivated by 5-AZA-CdR or DZNep have the potential to be reactivated by TSA. This provides a rationale for the use of HDAC inhibitors in combination with 5-AZA-CdR and DZNep to treat AML.

RESULTS

The triple combination of 5-AZA-CdR, DZNep, and TSA induced a remarkable synergistic antineoplastic effect against human AML cells as demonstrated by an in vitro colony assay. This triple combination also showed a potent synergistic activation of several key TSGs as determined by real-time PCR. The triple combination was more effective than the combination of two agents or a single agent. Microarray analysis showed that the triple combination generated remarkable changes in global gene expression.

CONCLUSIONS

Our data suggest that it may be possible to design a very effective therapy for AML using agents that target the reversal of the following three epigenetic "lock" mechanisms that silence gene expression: DNA methylation, histone methylation, and histone deacetylation. This approach merits serious consideration for clinical investigation in patients with advanced AML.

miR-125a regulates cell cycle, proliferation, and apoptosis by targeting the ErbB pathway in acute myeloid leukemia

microRNA profiling of acute myeloid leukemia patient samples identified miR-125a as being decreased. Current literature has investigated miR-125a's role in normal hematopoiesis but not within acute myeloid leukemia. Analysis of the upstream region of miR-125a identified several CpG islands. Both precursor and mature miR-125a increased in response to a de-methylating agent, Decitabine. Profiling revealed the ErbB pathway as significantly decreased with ectopic miR-125a. Either ectopic expression of miR-125a or inhibition of ErbB via Mubritinib resulted in inhibition of cell cycle proliferation and progression with enhanced apoptosis revealing ErbB inhibitors as potential novel therapeutic agents for treating miR-125a-low AML.